Conventionally, this kind of refrigeration cycle device is described, for example, in Patent Document 1. The refrigeration cycle device disclosed in Patent Document 1 includes a gas-liquid separator and a switching device. The gas-liquid separator separates a refrigerant into a gas-phase refrigerant and a liquid-phase refrigerant. The switching device switches a refrigerant circuit for circulation of the refrigerant to one of respective refrigerant circuits in a first mode and a second mode. Specifically, the gas-liquid separator can be configured to separate the refrigerant flowing out of an exterior heat exchanger into the gas-phase refrigerant and liquid-phase refrigerant and to allow the gas-phase refrigerant to flow out of a gas-phase refrigerant outlet while allowing the liquid-phase refrigerant to flow out of a liquid-phase refrigerant outlet. The refrigerant circuit in the first mode causes the liquid-phase refrigerant to flow from the liquid-phase refrigerant outlet of the gas-liquid separator into a second decompression device and an evaporator and to be then drawn into a compressor. The refrigerant circuit in the second mode causes the gas-phase refrigerant to flow out of the gas-phase refrigerant outlet of the gas-liquid separator and to be then drawn into the compressor.
In a refrigeration cycle device, to lubricate a compressor, oil is generally mixed into a refrigerant. Most of the oil is mixed into the liquid-phase refrigerant. Therefore, in the refrigeration cycle device of Patent document 1, when the refrigerant circulates through the refrigerant circuit in the second mode, specifically, when the gas-phase refrigerant is returned to the compressor, part of the liquid-phase refrigerant retained in the gas-liquid separator is mixed into the gas-phase refrigerant, thereby causing the oil to return to the compressor. In this way, the shortage of oil in the compressor can be prevented.